Method of carburation



Aug. 25, 1931. J. J. TRACY "ETHOD OF CARBURATION Filed Nov. 8, 1918 2 Sheets-Sheet 1 -Zifi ai 7 4a v a AM i jWOZ/VEYQ.

Aug. 25, 1931. J. J. TRACY 1,820,873

' .METHOD OF CARBURATION Filed Nov. 8, 1918 2 Sheets-Sheet 2 V/Al V1 H, Mus 72- 2 9 A 0 Z/ a o 7 f/vwz/a fi 7741-7. e7d/776JJ774C/ Patented Aug. 25, 1931 JAMES 3'. TRACY, OF CLEVELAND, OHIO METHOD OF .CARBURATION' Application filed November 8, 1918. Serial No. 261,674.

Numerous attempts have been made to provide for carbureting air with the heavier petroleum oils, and particularly kerosene, so as to secure a vapor suitable for continuous use in an explosion or internal combustion engine undervarying operating conditions such as are encountered where the engine is installed on an automobile, for example. Possibly the simplest method, and the one that would most naturally occur tothe experimenter, is to inject the kerosene or equivalent fuel oil into the proper volume of air to make the explosive mixture or charge, and then to heat such cold mixture in order to vaporize the fine particles of oil therein. The objection to this method is that a homogeneous mixture cannot be certainly or continuously obtained. Another of the methods attempted has been to make a rich mixture in a cold condition, that is, without heating either the liquid fuel or theair entering into such mixture, then vaporizing the mixtureat a high temperature and subsequently adding enough more air (a relatively large, volume) to make a propel explosive mixture. The difficulty with this methodof carburation is that the oil, even where it is thoroughly vaporized in the first etc is ver a )t to condense into a fo in such last step, with all the attendant difiiculties, such as improper combustion, waste due to the condensed oil finding its way past the piston to the crankcase, etc. Another method that has been attempted, with indifferent success, has been to burn a mixture of kerosene in a limited amount of air outside of the carbureter, and then to mix the products of incomplete combustion thus obtained with a larger volume of air to make the charge. The operation here is somewhat analogous to that of agas producer, it being claimed that a fixed gas 1s obtained.

In contradistinction to the foregoing methods, I propose to superheat all the air entering into the mixture so as to obtain a high enough temperature to vaporize the kerosene when it is sprayed or atomized into suchair. In other words, the latter supplies the latent heat of vaporization required to thoroughly and completely gasify the oil and produce a homogeneous mixture, but the resultant temperature is not so high that the efficiency of the engine is much reduced. In other words, such resultant temperature is approximately the minimum at which the oil is maintained in the state of a vapor, being much reduced when compared with the original temperature of the air prior to the admixture of the fuel therewith. The time elapsing between the vaporization and the admission of the mixture to the engine cylinder is made as short as possible so as to prevent any material cooling of the mixture and consequent condensation of the fuel, and if necessary the intake manifold is heated but just enough to maintain the mixture at the 35 criticaltemperature indicated.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the steps hereinafter fully described and particularly set forth in the claims, the annexed drawings and the following description setting forth in detail certain means and onemode of carrying out the invention, such disclosed means and mode illustrating, however, but one of various ways in which the principle of the invention may be used.

In said annexed drawings Fig. l is a side elevation, with parts shown in section, of a typical four-cylinder engine with intake and exhaust manifolds, and with s a carburetor and air heating means associated with such exhaust manifold, whereby my improved method of carburation may be carried out; Fig. 2 is an end elevation of the specially constructed manifold which forms afcature of the foregoing; Fig. 3 is a plan view of such manifold; Figs. 4 and 5 are sections thereof taken on the plane indicated by the lines 44i and 55, respectively, Fig. 1; Fig. 6 is a vertical sectional view on a larger scale of the carburetor; and Fig. 7 is a transverse section taken on a plane indi cated by the line 7-7, Fig. 6.

For practical reasons it is of course preferable to utilize the heat of the exhaust gases from the engine to raise the air used in carburation to the temperature hereinbefore indicated as necessary in order to achieve the results characterizing my improved method of operation. The mechanism illustrated in rectangularly related inlet and outlet openings 2 and 8. The outlet opening is connected to the intake manifold of an engine through an intermediate duct section in which is mounted a throttle valve 5 designed for automatic operation, for example, through a governor. on the engine, the usual manually operable throttle valve 6 being similarly mounted in the upper end of the carbureter casing.

Rising centrally from the bottom of the casing is a liquid fuel supply duct or nozzle 7, to the lower end of which is connected a fuel supply line 8. Surrounding the upper end of the nozzle, (see Fig. 6), so as to be freely slidable thereon, is an annular valve 9 which serves to partially fill the annular space between the nozzle and the surrounding casing wall, the remainder of such space being normally filled by a second annular valve 9% having its lower face angled as shown and surrounding the first'valve,'but adapted to be raised by the engine suction to .allow a corresponding volume of air past such first valve. A dash-pot 9 regulates the movement of said second valve, which also carries a needle valve 99 that controls the flow of fuel through the nozzle, the degree of taper of said needle valve bearing a predetermined relation to the angle of the suction actuated valve 9 Valve 9 is adapted to be raised from its normal position by means of a rock-shaft 10 mounted in the lower portion of the casingand to one side of said nozzle, said rockshaft being connected to said valve by a link 11 and being itself manually operable through means not shown. The connection between shaft 10 and the "annular valve 9 also includes a bar 12 of thermostatic metal, that is, a bar made up of two metals having relatively different coefiicients of expansion, so disposed that an increase in the temperature of the incoming air will cause said bar to bend or how concave downwardly, thereby correspondingly lowering said annular valve, and on the contrary should the air grow colder, the bar will bend in the opposite direction so as to raise such valve.

Abalanced valve 13 in advance of the rockshaft 10 is also operated by second bar 14 of thermostatic material to admit a supplemental supply of cold air, incase the air received from the heating means now to be described is too highly heated, as will be readily understood.

The exhaust manifold 15 previously referred to is of hollow U-shape in cross-section, as best shown in Fig. 4, and comprises a portion extending horizontally alongside the engine cylinders with suitable ports or openings 16 (four in number in the case illustrated), through which the exhaust gases from the corresponding cylinders are received into said manifold; also a downwardly directed portion or section through which connection is made to the muffler and the point of final discharge of the gases. A plate 17 attached to the front face of the manifold closes the space between the two arms of the U, thereby forming a second chamber 18 parallel and continuous with the' passage in the manifold proper, such chamber being open at the upper right-hand end of the manifold, as illustratedin Fig.1, and being closed at the lower left-hand end, save for a connecting duct 19 between such end and the intake opening 2 of the carbureter. The air for the latter, it will accordingly be seen, is drawn through the extended passage thus formed, which is in effect surrounded on three sides by the heated exhaust gases from the engine. In order to facilitate the absorption of heat by the air in the passage or chamher, the opposed walls of the latter are formed with staggered baffles 20, that not only serve to radiate the heat more readily, but also cause the air to follow a more or less tortuous path.

With the foregoing construction of air intake heater, I have found it possible readily to raise the temperature of the air to approximately 300 F. and higher, a range of from 280 to 310 F. being found satisfactory for the purpose in hand. The thermostatic connection between the rock-shaft and the annular valve in the carbureter will properly adjust and maintain such valve at the proper point for obtaining the most eflicient mixture when the operating temperature of the intake air is reached, as well as take care of variations in'such temperature when these occur. It is desirable,however, for reasons previously explained, to maintain this temperature as nearly constant-as possible at the point at which complete vaporization of the liquid fuel occurs, there being a loss in volumetric efficiency owing to the excess expansion of the air and thus of the charge if heated beyond this point. With the temperature of the intake air ranging between 280 and 310 F., a vaporized mixture of kerosene having a temperature of from to 220'F. will be secured, providing the proper amount of kerosene be injected in thoroughly atomized form. By reason of the special construction of heating means and the relative location of the carbureterwith respect thereto, and of the connection 21 leading to the intakemanifold, the mixture passes from the latter in the most direct fashion possible to the engine cyllnders. Furthermore, as shown in Flg. 5, a section of such manifold 1s in partial contact with the exhaust'manifold, which will a ssist in maintaining the temperature of the charge, without, however, raising the same, which isundesirable for reasons already pointed out.

The special construction of carburetor, as shown in detail in Figs. 6 and 7, contributes its share of the above described result, in that it insures the necessary thorough atomization of the fuel. In other words, an ordinary jet carburetor will not prove eiiective in handling kerosene, even when the proper'temperature conditions, etc., are provided, for, just as water if atomized or thrown into the air in'sufiiciently fine particles will vaporize at quite low temperature, whereas a stream of large particles passes through and precipitates even at a relatively high temperature, so the kerosene will persist in the form of H liquid particles unless properly atomized at the start, and at the first opportunity, as in passing around an angle in the lntake manii told, will precipitate out. In the present design of carburetor, however, it will be observed that the fuel is not directly sprayed as it emerges from the nozzle into the air current, but spreads film-wise over the flat circular'top of the inner valve 9, forming a thln circular film that peripherally overflows the valve and is whippedup when it reaches the edge of saidcvalve by the air passing through between such edge and the adjacent angular face of the valve 9*. The particles accordingly are so fine that they at once vaporize and by reason of the temperature control previously explained, such vaporous state isv I therefore particularly point out and distinctly claim as my invention 1. Themethod of carbureting air with ker- 'osene and the like, which consists in heating the entire volume of air to be utilized su'riiciently in excess of that at which such kerosene is maintained in vapor state to supply thelatent heat of vaporization, and then spraying the proper amount of such kerosene into suchheated air, while governing the spraying by the air temperature.

2. The method of carbureting air with kerosene and the like, which consists in heating substantially the entire volume'of air to r be utilized to a temperature sufficient to take up and maintain such kerosene in vaporized state, and then spraying the proper amount of such kerosene into such heated'air, while governing the spraying by the air temperature; I

3. The method of carbureting air with kerosene and the like, which consists in heating 'the'entirevolume of air to be utilized sufficiently in excess of that at which such kerosene is maintained in vapor state to supply the latent heat of vaporization, passing such airthrough an annular space, and supplying the proper amount of such kerosene in the form of a thin film overflowing into such space, while governing the supplying of the kerosene by the air temperature.

4. The method of 'carbureting air with kerosene and thelike, which consists in heating the entire volume of air to be utilized sufficiently in excess of that at which such kerosene is maintained in vapor state to supply the latent heat of vaporization passing such air through a constricted annular space, and supplying such kerosene in an amount graduated to the amount of air thus passing, in the form of a thin circular film peripherally overflowing into such space while governing the supplying of the kerosene by the air temperature.

5. The method of carbureting air with kerosene and the like, which consists in thermostatically governing the heating of theentire volume of air to be utilized suiiiciently in excess of that at which such kerosene is maintained in vapor state to supply the latent heat of vaporization, and then spraying the proper amount of such kerosene into such heated air, while governing the spraying by the air temperature.

6. The method of carbureting air with kerosene and the like, which consists in thermostatically governing the heating of the entire volume of air to be utilized to 280 to 310 F., and then spraying the proper amount of such kerosene into such heated air, while governing the spraying by the air temperature.

7. The method of carbureting air with kerosene and the like, which consists in 'thermostatically governing the heating of the entire volume of air to be utilized suificiently in excess of that at which such kerosene is maintained in vapor state to supply the latent heat of vaporization, passing such air through a constricted annular space, and supplying the proper amount of such kerosene in the form of a thin film overflowing into such space, while governing the supplying of the kerosene by the air temperature.

8. The method of carbureting air with kerosene and the like, which consists in thermostatically governing the heating of the entire volume of air to be utilized suificiently in excess of that at which such kerosene is maintained in vapor state to supply the latent heat of vaporization, passing such air through a constricted annular space, and supplying such kerosene in anlamount graduated to the amount of air thus passing, in the form of a thin circular film peripherally overflow i'ng into such space, While governing the supplying of the kerosene by the air temperature.

Signed by 'me, this 5th day of November. t 1918. V V v v a JAMES J. TRACY. 7 

